1. Field of the Invention
The present invention relates to an analog signal processing system which receives an input analog signal and performs various operations including addition, subtraction, multiplication and division by the use of processors such as micro-computers.
2. Description of the Prior Art
As a result of recent progress in digital circuit technology, processors such as small-sized micro-computers have been made available at lower cost, with consequent widening of the fields of application. In utilizing these processors with an analog system, it generally is necessary to provide an analog/digital converter (hereinafter referred to as A/D converter) on the input side of each processor for converting an analog signal to a digital signal, and also a digital/analog converter (hereinafter referred to as D/A converter) on the output side for converting a digital signal to an analog signal. Since the A/D converter is expensive and has a complicated circuit configuration, there exists a disadvantage that if an A/D converter and a micro-computer are employed to constitute a system, the entire equipment also turns out to be complicated, with increased cost. Particularly in the case where a plurality of input signals are processed, it is necessary to provide as many A/D converters as there are input signals, or to incorporate a multiplexer and perform analog-to-digital conversion after switching the input signals by the multiplexer, hence rendering the overall structure extremely intricate.